diff --git a/tsdb/head_read.go b/tsdb/head_read.go
index b95257c28a..438c7e6a4d 100644
--- a/tsdb/head_read.go
+++ b/tsdb/head_read.go
@@ -117,15 +117,19 @@ func (h *headIndexReader) PostingsForAllLabelValues(ctx context.Context, name st
 func (h *headIndexReader) SortedPostings(p index.Postings) index.Postings {
 	series := make([]*memSeries, 0, 128)
 
+	notFoundSeriesCount := 0
 	// Fetch all the series only once.
 	for p.Next() {
 		s := h.head.series.getByID(chunks.HeadSeriesRef(p.At()))
 		if s == nil {
-			h.head.logger.Debug("Looked up series not found")
+			notFoundSeriesCount++
 		} else {
 			series = append(series, s)
 		}
 	}
+	if notFoundSeriesCount > 0 {
+		h.head.logger.Debug("Looked up series not found", "count", notFoundSeriesCount)
+	}
 	if err := p.Err(); err != nil {
 		return index.ErrPostings(fmt.Errorf("expand postings: %w", err))
 	}
@@ -150,11 +154,12 @@ func (h *headIndexReader) ShardedPostings(p index.Postings, shardIndex, shardCou
 	}
 
 	out := make([]storage.SeriesRef, 0, 128)
+	notFoundSeriesCount := 0
 
 	for p.Next() {
 		s := h.head.series.getByID(chunks.HeadSeriesRef(p.At()))
 		if s == nil {
-			h.head.logger.Debug("Looked up series not found")
+			notFoundSeriesCount++
 			continue
 		}
 
@@ -165,6 +170,9 @@ func (h *headIndexReader) ShardedPostings(p index.Postings, shardIndex, shardCou
 
 		out = append(out, storage.SeriesRef(s.ref))
 	}
+	if notFoundSeriesCount > 0 {
+		h.head.logger.Debug("Looked up series not found", "count", notFoundSeriesCount)
+	}
 
 	return index.NewListPostings(out)
 }